twrp: Add support for TW_SECONDARY_BRIGHTNESS_PATH

 * Required for devices like Sony Huashan (dual backlighting paths)

Change-Id: I0f84623431aec91fafee6617c1d4c542e4566caf
diff --git a/minuitwrp/graphics_fbdev.cpp b/minuitwrp/graphics_fbdev.cpp
index 24294be..dc2bb2f 100644
--- a/minuitwrp/graphics_fbdev.cpp
+++ b/minuitwrp/graphics_fbdev.cpp
@@ -73,6 +73,16 @@
     }
     write(fd, blank ? "000" : brightness, 3);
     close(fd);
+
+#ifdef TW_SECONDARY_BRIGHTNESS_PATH
+    fd = open(TW_SECONDARY_BRIGHTNESS_PATH, O_RDWR);
+    if (fd < 0) {
+        perror("cannot open LCD backlight 2");
+        return;
+    }
+    write(fd, blank ? "000" : brightness, 3);
+    close(fd);
+#endif
 #else
 #ifndef TW_NO_SCREEN_BLANK
     int ret;
diff --git a/minuitwrp/graphics_overlay.cpp b/minuitwrp/graphics_overlay.cpp
index 5d759f6..84ea6e0 100644
--- a/minuitwrp/graphics_overlay.cpp
+++ b/minuitwrp/graphics_overlay.cpp
@@ -164,6 +164,16 @@
     }
     write(fd, blank ? "000" : brightness, 3);
     close(fd);
+
+#ifdef TW_SECONDARY_BRIGHTNESS_PATH
+    fd = open(TW_SECONDARY_BRIGHTNESS_PATH, O_RDWR);
+    if (fd < 0) {
+        perror("cannot open LCD backlight 2");
+        return;
+    }
+    write(fd, blank ? "000" : brightness, 3);
+    close(fd);
+#endif
 #else
     int ret;